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Topic: Drain on Starting Batteries? (Read 609 times) previous topic - next topic

Drain on Starting Batteries?

Last week, on Tuesday, I had the starting batteries load tested as they were not holding a charge.  Load test showed batteries good but needed a charge.  After load test, I put my charger on the batteries and after some period of time, the charger switched to maintenance mode.  Left charger on batteries for couple days then removed on Thursday.  The battery voltage remained at 12.8 for as long as the charger was connected but started declining each day since, measured 12.5 on Friday, 10.8 on Saturday and is the same today.  The coach was in storage when purchased and the charger I used was connected to the batteries at that time.  Batteries are Optima Red Tops.
What voltage should a battery charger charge to?
Once properly charged, how long should that charge last?  Other words, what kind of drain from parasitic loads should I expect?
Thanks for your input!
Bill and Joyce, The House2 and Dashboard Pig III
2000 U320 4210 CAI (The House2)
Build # 5733
2019 F150 King Ranch FX4

Re: Drain on Starting Batteries?

Reply #1 –
The main drain on mine are the tire pressure monitor repeater I installed and the Aux air pump for the air suspension and slide bladders.  Does your aux pump run often.

As far as how to charge the batteries you need to know the type of batteries.

1. Flooded
2. Gel Cell
3. AGM

Are the three main types.  Charge requirements is slightly different for each type.

I see you are in Spring Tx.  Hello from Waller Tx.
2006 Nimbus 336
Built 2005 may be one of the first coaches labeled Nimbus.
DEMCO Air-force One braking system.
Towing 2002 Jeep Wrangler Sport.
Road Master Falcon 5250 tow bar.

Re: Drain on Starting Batteries?

Reply #3 –
The main drain on mine are the tire pressure monitor repeater I installed and the Aux air pump for the air suspension and slide bladders.  Does your aux pump run often.

As far as how to charge the batteries you need to know the type of batteries.

1. Flooded
2. Gel Cell
3. AGM

Are the three main types.  Charge requirements is slightly different for each type.
2006 Nimbus 336
Built 2005 may be one of the first coaches labeled Nimbus.
DEMCO Air-force One braking system.
Towing 2002 Jeep Wrangler Sport.
Road Master Falcon 5250 tow bar.

Re: Drain on Starting Batteries?

Reply #4 –
Thursday 12.8
Friday 12.5
Saturday 10.8

OK, one of two things is happening:

Either you have a significant draw on them OR the batteries are shot.

Either will  give the readings you got.

Best to fully charge and then have them LOAD TESTED individually.

Wet cell and AGM batteries are pretty close in terms of their charging algorithms.  Bulk mode should be in the 14 VDC range.

If you have an ammeter, you could also measure the draw and easily calculate how long it should take for the batteries to discharge.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Drain on Starting Batteries?

Reply #5 –
Optima batteries used to advertise 270 days storage capability. Also had the industry's best warranty. But all this has changed. Walmart set the stage for a three year full warranty and after that nothing. Everybody followed to stay competitive. They are no longer built in the USA and no longer achieve there original build design goals. At one time they were rated #1 by me but no longer. They also lost 20% of there mass. Last start batteries I purchased were sealed lead acid from Napa and I pulled the stickers and top of with distilled water about twice a year. They don't loose much but they do loose some. The caps are screwed into the top of the battery and are flush under sticker. With everything off put a light bulb or test lamp across your ground post and ground. If it lights up you have something drawing power and sucking your batteries down. Also since your batteries are in parallel you also could have one battery drawing the others down. Isolate and recheck. If isolated do they all come down at the same rate or one faster... Replace as sets. I hate today's batteries!!
Scott

Re: Drain on Starting Batteries?

Reply #6 –
Even though they load test, one battery may have a weak or bad cell.

I realize you can't do a hydrometer test on Optimas, but I went through this with my flooded batts.They load tested, even didn't drop in voltage at the battery's as it went to start mode. In every way, they appeared OK, to the point I was going to change the starter.But a hydrometer test showed one weak cell.

I would do what Brett said, charge them separately, separating them, then do a load test on each one, let them sit overnight, and see what each battery does.

If anyone is weak or bad, they all need to be all replaced as a bank.

Chris


After I typed this, I agree with what Scott said. I learned all this about Optimas, because I run 2 in my race car.

I also now run two Interstate sealed group 31's for start batts in our U295 Cat. I have the Napa version in my wifes hot rod in the trunk. Both great quality, probably made by same company.
Chris and Tammy White  CDA Idaho
Previous owners 1997 U295 36' 3126 Cat 300 HP Build # 4998
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: Drain on Starting Batteries?

Reply #7 –
Really good points.  Thanks to all for your input.  My brain is starting to wake up as, like batteries, it sometimes needs a jump start!
I do not have a TPMS yet and rarely hear the aux pump running.
I will start with a current measurement and depending on that result will remove the batteries and have checked individually.
Thanks again and I will post my findings.
Bill and Joyce, The House2 and Dashboard Pig III
2000 U320 4210 CAI (The House2)
Build # 5733
2019 F150 King Ranch FX4

Re: Drain on Starting Batteries?

Reply #8 –
Again, to accurately do a load test, the batteries must be fully charged.

In they are not fully charged, you can get a false "bad" reading.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Drain on Starting Batteries?

Reply #9 –
Scott,

It makes no difference what country the batteries are made in as many of our cars and big rigs are made there.  It's the company and it's stockholders trying to squeeze the maximum profit out of the Optima's reputation and cutting corners every chance they get, whether it's labor or the construction materials.

In Sacramento, they are selling Interstate 31 series 1000 CCA for $80 out the door. Hard to pass up a set of three start batteries for $240. See FB Marketplace ad here: Redirecting...

Pierce

Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Drain on Starting Batteries?

Reply #10 –
I might add what I do is disconnect the batteries totally, from coach and each other. Charge them up, after charging check voltage, then for the next few days check the batteries voltage. You can then see if one or all of the batteries are losing voltage. If not then you have something in the coach running them down. 
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago
 

Re: Drain on Starting Batteries?

Reply #11 –
A battery can do just about anything you don't want it to do.

I let the clutch out too quickly on our Toyota, and the jolt killed the battery.

I have had a battery that could be turned on and off with a tap.

I had a battery that would charge fully with a smart charger, but immediately drop to under ten volts with a load attached and disconnected.

I guess the point is that a battery can act weird without any fault in the vehicle.
Matt B
1998 u-320